R help - Dec 2023 - Convert character date time to R date-time variable.

Colleagues,

I have a matrix of character data that represents date and time. The format of
each element of the matrix is
"2020-09-17_00:00:00"
How can I convert the elements into a valid R date-time constant?

Thank you,
John



John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;

Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;?

PI?Biostatistics and Informatics Core, University of Maryland School of Medicine
Claude D. Pepper Older Americans Independence Center;

Senior Statistician University of Maryland Center for Vascular Research;

Division of Gerontology and Paliative Care,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382

Look at the lubridate package in R.
Regards,
Tim

-----Original Message-----
From: R-help <r-help-bounces at r-project.org> On Behalf Of Sorkin, John
Sent: Thursday, December 7, 2023 11:22 AM
To: r-help at r-project.org (r-help at r-project.org) <r-help at
r-project.org>
Subject: [R] Convert character date time to R date-time variable.

[External Email]

Colleagues,

I have a matrix of character data that represents date and time. The format of
each element of the matrix is "2020-09-17_00:00:00"
How can I convert the elements into a valid R date-time constant?

Thank you,
John



John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;

Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;

PI Biostatistics and Informatics Core, University of Maryland School of Medicine
Claude D. Pepper Older Americans Independence Center;

Senior Statistician University of Maryland Center for Vascular Research;

Division of Gerontology and Paliative Care,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382



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?s 16:21 de 07/12/2023, Sorkin, John escreveu:
> Colleagues,
> 
> I have a matrix of character data that represents date and time. The format
of each element of the matrix is
> "2020-09-17_00:00:00"
> How can I convert the elements into a valid R date-time constant?
> 
> Thank you,
> John
> 
> 
> 
> John David Sorkin M.D., Ph.D.
> Professor of Medicine, University of Maryland School of Medicine;
> 
> Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;
> 
> PI?Biostatistics and Informatics Core, University of Maryland School of
Medicine Claude D. Pepper Older Americans Independence Center;
> 
> Senior Statistician University of Maryland Center for Vascular Research;
> 
> Division of Gerontology and Paliative Care,
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> Cell phone 443-418-5382
> 
> 
> 
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
Hello,

Coerce with ?as.POSIXct
Don't forget the underscore in the format.


as.POSIXct("2020-09-17_00:00:00", format =
"%Y-%m-%d_%H:%M:%S")


Hope this helps,

Rui Barradas


-- 
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www.avg.com

`anytime` was written for this:

  > anytime::anytime("2020-09-17_00:00:00")
  [1] "2020-09-17 CDT"
  > class(anytime::anytime("2020-09-17_00:00:00"))
  [1] "POSIXct" "POSIXt" 
  > 

Dirk


-- 
dirk.eddelbuettel.com | @eddelbuettel | edd at debian.org

On 12/7/23 08:21, Sorkin, John wrote:
> Colleagues,
>
> I have a matrix of character data that represents date and time. The format
of each element of the matrix is
> "2020-09-17_00:00:00"
> How can I convert the elements into a valid R date-time constant?
You will not be able to store these datetime values in an R matrix, at 
least as class POSIXct. You could with class POSIXlt, but I've not seen 
it used before but it does appear possible since matrices can contain 
lists.

R matrices do no provide the capability to assign attributes, so only 
atomic types and lists can be elements. If you wanted to maintain the 
same structure, your first step might be to coerce to a data.frame and 
then proceed, or to first construct a vector and then use as the first 
argument to `matrix`.


Best;

David
>
> Thank you,
> John
>
>
>
> John David Sorkin M.D., Ph.D.
> Professor of Medicine, University of Maryland School of Medicine;
>
> Associate Director for Biostatistics and Informatics, Baltimore VA Medical
Center Geriatrics Research, Education, and Clinical Center;
>
> PI?Biostatistics and Informatics Core, University of Maryland School of
Medicine Claude D. Pepper Older Americans Independence Center;
>
> Senior Statistician University of Maryland Center for Vascular Research;
>
> Division of Gerontology and Paliative Care,
> 10 North Greene Street
> GRECC (BT/18/GR)
> Baltimore, MD 21201-1524
> Cell phone 443-418-5382
>
>
>
> ______________________________________________
> R-help at r-project.org mailing list -- To UNSUBSCRIBE and more, see
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.